1. Field of the Invention
This invention relates to swimming pools and, more particularly, to apparatus for sensing the height of water in a swimming pool and for controlling the flow of water to the swimming pool from a location remote from the swimming pool.
2. Description of the Prior Art
There are several ways to control the height of water in a swimming pool. The simplest way to control the height of water in a swimming pool is by visual observation of the height of water in the pool, and upon visually determining that the water level is low, turning on a valve that allows water to flow to the swimming pool until the desired water level is observed. When the desired water level is observed, the water valve is manually closed, stopping the flow of water to the swimming pool.
There have been other systems suggested for automatically controlling the height of water in a swimming pool, one such being suggested by U.S. Pat. No. 2,739,939. In the '939 patent, a float control operates a valve when the water level is low. When the water level is brought to a predetermined height, the float rises and turns off the valve. The system is not unlike the conventional float control valve used to control the height of water in a toilet tank.
Another automatic system for controlling the height of water in a swimming pool is shown in U.S. Pat. No. 3,908,206. The swimming pool in the '206 patent is an above-ground swimming pool, and the water height control system is disposed adjacent to the swimming pool. A float is again used to control a valve which turns on and off a flow of water.
In addition to the two patents discussed above, there have been other patents which include systems for automatically sensing the level of a liquid. Such liquid level patents include U.S. Pat. No. 352,647, U.S. Pat. No. 2,070,617, U.S. Pat. No. 2,305,102, and U.S. Pat. No. 4,014,010.
While none of the four patents identified in the preceding paragraph are concerned with swimming pools, they each include means for sensing the height of a liquid in a tube of some type. In the '647 patent, a light source and a light sensitive element are disposed on opposite sides of a tube, with an opaque float disposed in the tube. The float is disposed between the light and the light sensitive element. When the float sinks with the level of the liquid in the tube, the resistance in an electrical circuit is changed and an alarm bell sounds.
In the '617 patent, light sources and light sensitive elements are disposed on opposite sides of a tube in which the water level is indicated. An opaque float is also used in the tube. The changing water level causes the float to move, thus allowing light rays from the light sources to impinge upon light sensitive elements. Appropriate relays are used to control the flow of the water between the predetermined minimum and maximum heights.
A light beam is used in conjunction with the '102 patent, but no float is used.
In the '010 patent, a light source and a photo cell are disposed on opposite sides of a tube and an opaque float is disposed within the tube. Movement of the opaque float with respect to the light source and the photo cell controls an electrical circuit. When the float drops from between the light source and photo cell, an output to an alarm system which is activated, indicating that the fluid level has dropped below a predetermined minimum.
In the two groups of patents, the patents concerned with swimming pools utilize floats to control the flow of water to a swimming pool. In the second group of patents, which have nothing to do with swimming pools, tubes are connected to a liquid tank of some kind, and a sensing system is used to determine the height or quantity of liquid (water) in the tank. In the '617 patent, the liquid sensing system also results in the actuation of a valve to keep the level in a boiler within predetermined limits. However, the other patents in the group are simply for reference purposes with respect to the height of the liquid and are not connected to a fill system. Moreover, all of the systems, in both groups of patents, are disposed adjacent to the liquid supply whose height they are concerned with. For swimming pools, it is advantageous to have the height sensing apparatus, particularly if it is associated with electricity, to be located remotely from the swimming pool so as to isolate the electrical system from the water system as much as possible. The apparatus of the present invention includes the remote sensing of the water height of a swimming pool and the electrical system(s) associated with the sensing and control system is thus isolated from the swimming pool.